Vehicles may travel according to trip plans that designate speeds of the vehicles at different locations along a route. The trip plans can be used to autonomously control the vehicles or to provide instructions to an operator of a vehicle in order to instruct or coach the operator on how fast the vehicle should be moving at different locations along the route. For example, TRIP OPTIMIZER by General Electric Company can generate trip plans to dictate how fast trains should move at different locations along a route. The trip plans may be created to reduce fuel consumed and/or emissions generated by the vehicles relative to the vehicles being manually controlled, the vehicles traveling at speed limits of the route, or the like.
One problem that can arise with trip plans is the detection of when a vehicle begins moving. Some vehicles, such as trains, can move for a significant distance before movement is detected. While speed sensors can be used to detect when an axle or wheel of a vehicle is rotating to identify movement of the vehicle, a wheel may be slipping relative to the surface being traveled upon. Rotation of a wheel and/or axle may be incorrectly identified as movement of the vehicle when the rotation is not moving the vehicle forward.
As a result, trip plans may begin and/or end at lower speed limits or speed points. A vehicle is controlled manually until the vehicle is brought up to the initial speed designated by the trip plan and/or the vehicle is controlled manually after the vehicle slows below the lower speed limit. Some vehicles may need to accelerate for significant distances in order to reach the lower speed limit of a trip plan and/or to slow down below the lower speed limit for significant distances in order to stop. For example, long freight trains may need to travel for a significant period of time before reaching the speeds designated by a trip plan and/or to stop after slowing below the lower speed limit of the trip plan. The travel of the vehicles at speeds below the lower speed limits of the trip plans can be less efficient than the travel according to the trip plan. As a result, the vehicles are consuming more fuel and/or generating more emissions than necessary.
Moreover, traveling according to trip plans can provide various benefits, such as fuel economy, as long as the objectives of the trip plan are relevant to the operations of the vehicle system. For example, the objective of increasing fuel efficiency is beneficial to the vehicle system as the vehicle system travels along an open section of the route at a planned running speed, but the same trip plan is not as beneficial if the section of the route has maintenance, congestion, or other constraints that limit the speed of the vehicle system to a speed below the planned running speed. In another example, the objective of increasing fuel economy is also not relevant near the designated stop locations (including the arrival location) along the route because the vehicle system has to travel at slow speeds to stop at the stop locations. Due to these issues, some operators of the vehicle system may choose to not follow the trip plan.